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Fronkie

720 repower

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Fronkie
Ok, it is time to make a decision. I just happened to pick up another 720 after selling my other, and this Onan is tired. Even though it idles and runs fine, it will not handle the 60" flail mower under load. The rings on the left side were stuck when I got it and I had to helicoil that same side. I figure it is time to look at my other options. Since I do not have any experience with rebuilding engines, I have no idea what that would cost (I know the parts can be quite pricey). I've looked at the two repower kits and they are priced the same. I know several on here have gone with the Honda repower. What makes that better than the briggs 23hp? Any input would be great.

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305SS
It`s in the name. If it is any thing like are fourwheel engine that my wife and I bought in 2000. It has 1800 miles and over 200 hours on it. I run treated premium gas and change the oil once a year. I have put one battery and air cleaner in it. She likes to use it in the garden for pulling a 3' springtooth. It has been a very good machine for me.

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RayS
Not sure which Onan is in your tractor but the link below has some Onan options. Maybe alot easier than doing mods. http://cgi.ebay.com/CCK-ENGINE-LONG-BLOCK-ONAN-110-3422-11-NEW-OLD-STOCK-/140388409395?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item20afcd2033

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gregnorth
i like the looks of the briggs. red was never my favorite color. if your onan is a cckb i might be interested in your old flywheel. the magnets in mine are beginning to desinigrate. later greg

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D-17_Dave
At one time the Briggs engines were not available, they may be now. The CCK engines use the same block so any accessories such as remote or block mounted filters are bolt on things. Just unplug the ports and bolt the filter base to the new block. The variables will be the crankshaft used. The CCK engines were used in almost every application imaginable. You'll need to have the seller look up your spec number and cross it over to your engine or you'll be forced to open up a new short block and swap the cranks.

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midnightpumpkin
quote:
Originally posted by wilm169
I have talked to the get Ray has listed, and he has not got the right crank in his we need.:(:(
Wilm, Did you talk to the seller about the other short blocks he has listed? [url]http://cgi.ebay.com/SHORT-BLOCK-ONAN-CCK-CCKA-CCKM-MS-2504G-110-3422-13-NOS-/310204656232?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item4839a36a68[/url] 2nd question, will the accessories from a CCKB bolt on to a CCKA? John U

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Ronald Hribar
I would check with Jim's Repair in MN. He has done Vanguard conversions in several different makes of tractors He has developed kits for several of them http://www.jimsrepairjimstractors.com/

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xenon172
I'd get a price from a competent shop in your area for a rebuild before making a decision. The Onan is great engine and the cost may not be as bad as you think especially compared to the cost of a replacement engine.

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D-17_Dave
John, I think Levi's answer indicated that he had spoken to the seller and he didn't have the correct crank for this application. You'll find that most of these engines are made for generator service rather than the tractor application we use. Keep watching though, I picked up a new short block for around 400.00 including shipping. Deals can be found if you watch for them. The short block assemblies between the CCKA's and KB's are fully interchangeable. I have about all I need to install a diesel engine in a spare tractor. It has been a lot of work and a lot of custom parts and I have been short of time with too many projects to get back into it lately. But, if I succeed in getting it up and running it will be a fully functional tractor. There have been several conversions I have seen but most miss having it where you can still use all the attachments.

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D-17_Dave
Keep in mind that the price for a rebuild on your engine should render the results of another 20 plus years. These older cast iron engines will take a lot more abuse than the newer alum. blocked engines.

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GregSch
I put a Briggs 23hp in my 9020 in 2003. You can't beat the newer style ignition. No points and condensor. It doesn't require any mintenance. I think it is more efficient than the Onan. Mine was tired when I replaced it but it took 6 gallons of fuel to mow my yard with the Onan. I mow it now with about 4 gallons. After seven years use the only engine repair I have had to make was a valve adjustment this year. The valves got tight over time and it made it hard for the starter to turn it over. I replaced the fuel pump on the Onan every 2 or 3 years. The air cleaaner on the Briggs has a foam outer filter on a paper filter. I wash and re-oil the foam outer filter every couple months. I used the same paper filter for 7 years. Don't underestimate the amount of work to do an engine swap but to me it was well worth it.

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Fronkie
Had a thought...what would be the possibility of just new rings? The tractor did sit for several years and rings were stuck on the one side. What are the chances of just replacing the rings?

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JimDk
Greg, Did you pull that piston out after getting it loose? I repaired an Allis "C" farm tractor which had two stuck pistons. After much soaking I removed the pistons and both had rings which did not expand (stuck) in the grooves. I had to soak them overnight in my parts washer to free them. There is a chance, if your ring grooves and cylinders are in spec, you could benefit from just a ring job. You would need to tear it down and measure everything. Unless you are doing the job yourself, it probably would not be cost effective, though. Labor cost would be high and you would need new seals and gaskets plus the rings. Good luck, Jim

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midnightpumpkin
I have to wonder what would happen if you pulled the plugs and filled the cylinders with Jim's magic rust buster (50% Auto Trans Fluid/50% Acetone) and let it soak for a couple of days. Then turn the engine over to pump the rust buster out. I would then start it and let it run a few minutes to kill any mosquitoes within 1/2 mile and then change the crankcase oil. The only investment would be time and a little oil. Jim's magic rust buster has worked for everything I have tried it on. Don't see why it wouldn't free up stuck rings if that is the culprit. John U Some may say the heat has gotten to old John!

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JimDk
John, I can't take credit for the rust-buster formula. I pirated it from the Allis Chalmers farm tractor forum. It does work, though some caution must be taken. It will dissolve some plastics, and as with any chemical, protect your eyes and skin. I agree that it would not hurt to try it in an engine that was stuck.

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Fronkie
Put marvelous mystery oil in and let it set over the weekend. Blew it out today. I was able to run the Flail mower in most stuff. It was a bit wet with the rain, but the 720 was still able to handle the load. So...as for now, we'll see how long we can hang on to this original onan before I dump a ton of money into it.

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